This invention relates to couplers and more particularly to couplers for interconnecting scaffolding.
Scaffolding is commonly constructed from lengths of steel or aluminum tubes interconnected to each other to form an open structural framework. The size and configuration of the structure depends on the application. The interconnection of the tubes is normally made by two right angle couplers (xe2x80x9cdouble couplersxe2x80x9d) which are joined together. One of these double couplers can interconnect two of the three tubes that will normally meet at a right angle crossing of a scaffold structure. A second double coupler is required to interconnect a third tube to the first two.
The couplers are normally locked to the tubes by one or more nut and bolt locking devices. However, such couplers suffer from disadvantages. Their fastening and unfastening is time consuming and is inconvenient in requiring use of a wrench. Additionally, two hands are normally required to hold the coupler during the initial stages of fastening and the nuts and bolts are often corroded, making it difficult to thread and tighten the nuts. Also, the locking device may be under or over tightened on the tubes, leading to slipping or thread stripping respectively, which may compromise the safety of the scaffold structure.
The invention may be summarised according to a first broad aspect as a coupling apparatus for interconnecting three scaffold members comprising: a support coupler and two connector couplers for attachment to three scaffold members; the support coupler having a base interconnected to the connector couplers, a lever hinged to the base, and a locking device, the base and the lever defining a pocket for laterally receiving a length of a scaffold member; the connector couplers each defining a pocket for receiving a length of a scaffold member and having a locking device; each of the locking devices being movable from a release condition, to allow a scaffold member to be positioned in or removed from the pocket, to a locked position, to secure the scaffold member in the coupler; wherein the pockets are oriented to secure three scaffold members at relative angles to each other.
The invention may be summarised according to a second broad aspect as a two coupler apparatus for interconnecting two scaffolding members wherein at least one coupler is defined by: a base interconnected to a second coupler; a lever hinged to the base, the base and the lever defining a pocket for laterally receiving a length of a scaffold member; an arm hinged to the base; the lever having an slot sized to receive the arm; the arm defining a hole positioned to extend beyond the lever when the arm is within the slot; a wedge adapted for insertion through the hole to slidably move against the lever when the arm extends within the slot to wedge the arm within the lever whereby the scaffold member is locked within the at least one coupler.
The invention may be summarised according to another broad aspect as a two coupler apparatus for interconnecting two scaffolding members wherein at least one coupler is defined by: a base interconnected to a second coupler; a lever hinged to the base, the base and the lever defining a pocket for laterally receiving a length of a scaffold member; an arm hinged to the base, the arm having a protrusion at a free end; the lever having an slot adapted to receive the arm; a circular wedge pivotally mounted on the arm, the circular wedge circumferentially increasing in thickness to define a cam surface for engagement with the protrusion; the circular wedge being rotatable on the arm between the lever and the protrusion in a direction of increasing thickness to create a wedging action between the protrusion and the cam surface acting to press the lever onto the scaffold member to lock the scaffold member within the pocket.
The invention may be summarised according to a further broad aspect as a two coupler apparatus for interconnecting two scaffolding members wherein at least one coupler is defined by: a base interconnected to a second coupler; a lever hinged to the base, the base and the lever defining a pocket for laterally receiving a length of a scaffold member; an over-centre hand-lever mechanism for intercoupling the base and the lever, the over-centre hand-lever mechanism having an adjustable length and being selectively actuatable when intercoupling the base and the lever to lock the lever and the base to a scaffold member.
Advantageously, the triple coupler allows three scaffold members to be interconnected with only one coupling apparatus thereby replacing the two double couplers normally used. Assembly is then achieved by the handling of one apparatus instead of two.
Additionally, the angle between the three scaffold members can be fixed by the triple coupler. This eliminates the need to adjust the angle of a second double coupler relative to a first double coupler as is necessary where two double couplers are used.
Specific embodiments of the couplers, namely the wedge coupler, the circular wedge coupler and the hand-lever coupler, have the advantage that they do not rely on threaded bolts and nuts to fasten the couplers around the scaffold members. This eliminates the problems of stripped or rusted threads associated with bolt-and-nut locking devices.
Additionally, the hand-lever coupler may be fastened or unfastened quickly without the use of any hand tools.
Also, the wedge coupler and the circular wedge coupler are simple to fabricate, may be fastened or unfastened rapidly and the circular wedge coupler has no separable parts.
Other aspects and features of the invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.